I think I stated this before but- I know the reason most all of mine got sick was because I just got them (stress) plus we had an extremely cold night come out of nowhere (compromised immune system) and the next day they were noticeably sick.

I keep them on my porch still but now when we are going to have colder nights I make sure to give them PLENTY of newspaper to shed and nest, plus some towels over the tubs, and a plastic sheet over the lot of them. Just remember to remove in the morning.

I am glad your guys are getting noticeably better!